Chemical decomposition of 2,4,6-trichlorophenol by ozone, Fenton's reagent, and UV radiation

The kinetics of the decomposition of 2,4,6-trichlorophenol by ozonation, by Fenton's reagent reaction, and by a polychromatic UV radiation is investig ated from experiments performed in a batch reactor. In each oxidation syste m, the degree of removal of the organic compound from water is evaluated an d the influence of the operating variables is established. The ozonation pr ocess is conducted at pH = 2 and in the presence of radical scavengers: In these conditions the kinetic constants and reaction orders for the direct r eaction between ozone and that organic compound are deduced by using a mode l based in the film theory. The oxidation by Fenton's reagent (Fe2+ ion and H2O2), a generating system of hydroxyl radicals, leads to the evaluation o f pseudo-first-order rate constants for the global reaction and to the dete rmination of the kinetic constant for the direct radical reaction. Finally, the quantum yields in the photodecomposition process are determined from t he rate equation, with the radiation flow rates absorbed previously calcula ted by means of a radiation source emission model.